I just came across a 1935 article by Trotsky on Marxists’ attitude to
religion. I can’t find it online, but here is a quotation. Highly
relevant to our position for religious freedom, for workers’
mobilisation to defend it and defend religious minorities against
fascist attack – but against cross-class political fronts with those
claiming to represent religious workers (as in Respect).

“Radical” refers to the main party of the French bourgeoisie, which
was in a popular front with the French Socialist and Communist parties.

**

“Of course, supporting the *church* is out of the question. For us it
can only be a question of whether or not we support the *political
struggle* of Catholics and Protestants to remain Catholics and
Protestants and to act as such. The answer to this question is yes. It
goes without saying that we do not in the process commit ourselves to
supporting religion and the church, but rather emphasise, insofar as
possible, our opposition to religion and the church.
“However it is not clear to me what that has to do with the slogan
‘Down with the Radical ministers’ (not just the ex-ministers). This
slogan is nothing more than the demand to break with
*class-collaborationist front*. Since the reformists and the
Stalinists refuse to carry out this break, they will be compromised in
the eyes of the workers. Hence the slogan ‘Bourgeois Radicals out of
the People’s Front’ is a completely correct Marxist slogan at the
present time.
“Let us suppose, and this is not so difficult to imagine, that
tomorrow the [French] fascists begin to storm Freemason temples or
smash Radical newspapers (and this has already occurred episodically).
It goes without saying that the workers will take to the streets to
help defend the Freemason temples. But what is Freemasonry. It too is
a kind of church charged with making the free-thinking petty
bourgeoisie pliant to the interests of high finance. Can we support
Freemasonry? No, never. We can and must, however, defend its right to
exist against the fascist attacks, with gun in hand if necessary. To
be capable of this, the working class must stay revolutionary-minded
and ready to fight. However, the People’s Front makes this impossible.
For this reason it is necessary to drive the Radical bourgeoisie out
of the People’s Front to be able to defend even Freemasonry, should
the occasion arise. There isn’t the slightest contradiction here.”